In image capturing apparatuses using image pickup elements, such as CMOS image sensors, fixed pattern noise arises from readout circuits of the image pickup elements. As a method for obtaining a high-quality image by reducing this fixed pattern noise, there is generally known a method for correcting fixed pattern noise by subtracting pre-stored data from image data. For example, PTL 1 discloses a method for correcting fixed pattern noise of an image by using pre-stored one-dimensional data, depending on shooting conditions.